Redundant Generator Control

ABSTRACT

A generator system may include redundant control. The generator system may include any combination of redundant controllers, redundant communication paths, or other redundant control. A generator system may include an electrical bus, a first generator controller, and the second generator controller. The first generator controller may control a first generator breaker for connecting a first generator to the electrical bus and configured to control an external breaker for selectively connecting the electrical bus to an external source. The second generator controller may control a second generator breaker for connecting a second generator to the common bus and configured to control the external breaker for selectively connecting the electrical bus to the external source.

This application is a continuation under 35 U.S.C §120 and 37 C.F.R.§1.53(b) of U.S. non-provisional application Ser. No. 14/262,419, filedon Apr. 25, 2014, which is hereby incorporated by reference in itsentirety.

TECHNICAL FIELD

This disclosure relates in general to a redundant generator control, ormore particularly, multiple generator controllers each capable of atleast one redundant control feature for a generator system and/orconnected with redundant communication paths.

BACKGROUND

The reliability of power companies depends on many factors such as theweather, usage spikes, short circuits, accidents or other damage totransmission lines or power stations. Certain locations may beparticularly prone to blackouts. Low lying areas may be susceptible tofloods. Coastal areas may be susceptible to hurricanes. High usagegeographic areas may be susceptible to rolling blackouts.

Any breaks in power utility service may be unacceptable to customers,and some businesses may have mission critical systems, such as computersystems in call centers or refrigerators in grocery stores, that rely onconstant power. In other businesses such as hospitals, lives may be lostif the power to a respirator is interrupted. These customers may rely ona backup source of power.

One backup source of power is a generator. The generator, or multiplegenerators, is connected to the system in addition to the power utilityservice. Multiple points of failures exist with a generator system. Insome examples, when any one of multiple devices experiences a failure,the entire generator system is shut down.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary implementations are described herein with reference to thefollowing drawings.

FIG. 1 illustrates an example system including redundant generatorcontrollers.

FIG. 2 illustrates an example system including redundant communicationpaths.

FIG. 3 illustrates an example system including redundant generatorcontrollers.

FIG. 4 illustrates an example redundant controller.

FIG. 5 illustrates example flowchart for operation of the redundantcontroller of FIG. 4.

DETAILED DESCRIPTION

An engine-generator set, which may be referred to as a generator or agenset, may include an engine and an alternator or another device forgenerating electrical energy or power. One or more generators mayprovide power to a load through a generator bus. The generator bus is anelectrical conductive path and may be selectively connected throughmultiple circuit breakers or other types of switches to the generators,the utility system, and other devices.

Consider a generator system including two generators connected to agenerator bus through circuit breakers and a utility connection coupledto the generator bus through a utility breaker. Each generator mayinclude a local generator controller, and a utility controller (e.g.,programmable logic controller) may manage the utility breaker. In otherexamples, the utility control may also control breakers between thegenerators and the generator bus. These types of generator systemssuffer from several single points of failure, such as the utilitybreaker controller, the power supply to the any controller, andcommunications between the utility breaker controller and generatorcontrollers, as described below.

If a generator controller fails or if the communication path between agenerator controller and corresponding generator fails, thecorresponding generator stops operating and no longer supplies power tothe generator bus. A generator controller failure may also lead to anoverload on the remaining generators, which may cause the remaininggenerators to fail. The generator corresponding to the failed generatorcontroller may be operable, but cannot be utilized by the generatorsystem.

If the utility controller fails, the utility cannot be connected ordisconnected from the generator bus. Thus, the generator system maycontinue to run when no longer needed, or in other scenarios, thegenerator system may not be able to supply power to the load because thegenerator bus is electrically connected to a dead or inoperable utility.When the utility controller also controls the generator breakers or theutility breaker is interlocked with the generator breakers, a failure atthe utility breaker or utility controller could render all generators inthe generator system unusable.

The following examples eliminate many of the single points of failure inthe generator system with one or more redundant controllers. A redundantcontroller may be a generator controller that is primarily associatedwith a particular generator but may also issue command signals to othergenerators or any of the circuit breakers. A generator controller may beconsidered redundant because the generator controller duplicates one ormore functions of another generator controller. Two or more generatorcontrollers may be considered redundant because the generatorcontrollers may independently control an external circuit breaker. Anygenerator controller or the utility controller may fail and a remainingcontroller is still operable to control the utility breaker. Thegenerator controllers may be connected to redundant communication pathsin which more than one communication path exits between a generatorcontroller and an external device. Additional single points of failurethat may be avoided using redundant controllers or communication pathsmay include the contacts between the various devices in the generatorsystem and the bus or communication paths.

FIG. 1 illustrates an example system including redundant generatorcontrollers. The system includes generators 101 a and 101 b andcorresponding controllers 100 a and 100 b. Additional generators may beincluded. The generators 101 a and 101 b are electrically connectedthrough the generator bus 11, which is also connected to the utilitysystem U through a circuit breaker 12. Generator 101 a is connected to aload L by a circuit breaker 13 a, and generator 101 b is connected tothe load L by a circuit breaker 13 b. Each of the generators 101 a and101 b may be independently connected to the utility system U.Additional, different, or fewer components may be included in thesystem. FIG. 2 illustrates another system including redundant generatorcontrollers and a switch controller 103.

The generators 101 a-b may also include a fuel supply, a speed governor,a cooling system, an exhaust system, a lubrication system, and astarter. Additional, different, or fewer components may be included.Example types of generators include towable generators, portablegenerators, marine generators, industrial generators, residentialgenerators or other standby generators. The generators may be portableor permanent.

The generator controller 100 a controls circuit breaker 13 a forselectively connecting generator 101 a to generator bus 11 andcontrolling an external breaker (e.g., circuit breaker 12) forselectively connecting the generator bus 11 to an external source. Thegenerator controller 100 a may also control circuit breaker 13 b forselectively connecting generator 101 b to generator bus 11. In someexamples, the external source is a utility power system or anothernon-generator power source. Additional non-generator power sourcesinclude solar power, wind turbines, hydroelectric power, batteries, andother sources.

The generator controller 100 a is connected both through generator bus11 and a communication path to generator controller 100 b. In onealternative, the separate communication path is omitted and thegenerator bus 11 also serves as the communication path. The generatorcontroller 100 b is also operable to send a command for the externalbreaker (e.g., circuit breaker 12) to selectively connect the generatorbus 11 to the circuit breaker 12. The generator controller 100 b alsomay control circuit breaker 13 b for selectively connecting generator101 b to generator bus 11 and circuit breaker 13 a for selectivelyconnecting generator 101 a to generator bus 11.

Any of the generator controllers 100 a and 100 b may generate switchcommands for any of the circuit breakers 12, 13 a, and 13 b to connectrespective devices to the generator bus 11. The switch command mayinclude any combination of an origin address, a destination address, aclose code, and an open code. The origin address may identify thesending generator controller, and the destination address may identifythe circuit breaker. The close code instructs the circuit breaker toconnect the respective device to the generator bus 11, and the open codeinstructs the circuit breaker to disconnect the respective device fromthe generator bus 11.

Any of the generator controllers 100 a and 100 b may monitorcommunications sent by other generators controllers or by the optionalswitch controller 103 of FIG. 2. The communications may include switchcommands between controllers and circuit breakers, operating controlsfor the generators, or status signals reporting operating parameters forthe generators.

The communications may be monitored because communications from thegenerators controllers are sent to all connected devices. For example, aswitch command from the generator controller 101 a to circuit breaker 13a would also be sent from the generator controller 101 a to thegenerator controller 101 b and optionally, other devices. In anotherexample, a switch command for the circuit breaker 12 from the generatorcontroller 101 b would also be received at generator controller 101 a.

The communication may be monitored because communications in thegenerator system are routed through the generator bus 11. Thecommunications may be a high frequency signal modulated on the powersignal of the generator bus 11. The communications may be a publicationand subscription messaging system in which messages or commands from anyof the controllers may be subscribed to by other devices.

Any of the generator controllers 100 a and 100 b may monitor theexistence of communications between any of the controllers and any ofthe circuit breakers. For example, generator controller 100 a maymonitor communications between the generator 101 b and the circuitbreaker 12 to identify when a break in those communications or anabsence of those communications occur. The break or absence indicatesthat the generator controller 101 b is not controlling the circuitbreaker 12 for the external source. In response to a break or absence ofthe communication, the generator controller 100 a may take over andcommunicate (e.g., send commands, receive status signals) with thecircuit breaker 12. In response to a break or absence of thecommunication, the generator controller 100 a may communicate directlywith the generator controller 100 b to troubleshoot the break or absenceof communication.

Any of the generator controllers 100 a and 100 b may send messagesaddressed to the other controllers in the system. The messages mayinclude at least one operating parameter of the sending generator, anidentifier for the sending generator, or a peer generator command fromthe second generator.

The identifier may include a code that is associated with the type ofsending device (e.g., G for generator, S for transfer switch, or U forutility). The identifier may include a serial number of the sendingdevice, a model number of the sending device, a rating of the sendingdevice, or a network address of the sending device. The rating of thesending device may be a power rating (e.g., 20 kW, 40 kW, or anothervalue), a voltage rating (e.g., 50 V, 120 V, 240 V, or another value),or an age rating (e.g., number of operating hours, model year, oranother value).

Any of the generator controllers 100 a and 100 b may exchange operatingparameters. The operating parameter of the sending generator maydescribe a speed, an output voltage, an output phase angle, or a breakerstatus of the sending generator. The operating parameters may includesettings or outputs from the generators 101 a or 101 b. The operatingparameters may be inferred from settings (e.g., when the generator isset to output 120V, the operating parameter indicates 120V even thoughactual levels may vary). The settings may include a power setting, avoltage output setting, a frequency setting or another output setting.Alternatively, the operating parameters may include measured datacollected from one or more sensors. The sensors may include anycombination of a voltage sensor, a current sensor, a tachometer, atorque sensor, a deflection sensor, a dynamometer, a positional sensor,or a revolution sensor.

The peer generator command may be sent from any of the generatorcontrollers 100 a and 100 b to any other generator controller. The peergenerator command may instruct the receiving generator controller tobegin running, stop running, or to adjust output. The output adjustmentmay be an engine speed, an output power, a phase angle, or an outputvoltage. The output adjustment may be a target level, a percentageadjustment, or an absolute adjustment. The peer generator command may begenerated and transmitted to the receiving generator controller inresponse to one or more operating parameters from the receivinggenerator controller in the past.

For example, the generator 101 b may have been running at 50% for someamount of time, which is detected by the generator controller 100 abased on the operating parameters. The generator controller 100 a maydetermine that the generator controller 100 b experienced a failure(e.g., through direct communication, monitored communication, or anotherscenario). In response, the generator controller 100 a may send peergenerator commands to the generator 101 a to cause the generator 101 ato operate at the last known configuration, which in this case is 50% ofcapacity.

In another example, generator controller 100 a may determine that thegenerator controller 100 b experienced a failure, and in response,generate a start command for the generator 101 b to start running. Inother words, when the generator controller 100 a determines thatgenerator 101 b has stopped running and the generator controller 100 bhas failed, the generator controller 100 a steps in for generatorcontroller 100 b to start the generator 101 b.

Any of the generator controllers 100 a and 100 b may generate loadshedding commands in response to remove or add portions of the load tothe generators 101 a-b. Generator controller 100 a may generate andtransmit a load shed command to one or more switches to remove a portionof the load from generator 101 b, and generator controller 100 a maygenerate and transmit a load shed command to one or more switches toremove a portion of the load from generator 101 b. The switches may bearranged in an array to put configurable loads on the generator bus 11or directly coupled to a generator.

Either of the generator controllers 100 a and 100 b may generate switchcommands for the external switch (e.g., utility circuit breaker 12).However, the generator controllers should not generate conflictingcommands. Several techniques are possible to avoid conflicting commands.

In one example, the generator controllers may negotiate a priorityalgorithm to determine which of the generator controllers has priorityfor controlling the external breaker. The priority negotiation algorithmmay be executed at the generator controllers or by logic co-located withthe circuit breaker (e.g., switch controller 103). The generatorcontrollers may exchange messages as described above, and the prioritynegotiation is executed by one or all of the generator controllers. Thepriority negotiation algorithm determines which of generator controller100 a and 100 b takes priority based on any combination of a firstgenerator to power up, a first generator controller to power up, aserial number priority, a model number priority, a capacity priority, afirst generator to close to the electrical bus, or a random orderpriority. The priority negotiation algorithm may be configurable or userselected.

The generator controller that has priority under the prioritynegotiation algorithm may be referred to as the priority controller andthe other controllers in the system may be referred to as secondarycontrollers. By default, all controllers may initially be designated assecondary controllers. The generator controller of the first generatorto power up may designate itself the primary controller, which isadvertised by sending messages to other controllers as they come online.

In other examples, the priority may be re-negotiated each time that anew generator controller comes online. In one example, the generatorcontrollers exchange serial numbers of generator controllers orgenerators and the highest (or lowest) serial numbers is designated asthe priority controller. In one example, the generator controllersexchange model numbers of generator controllers or generators and thehighest (or lowest) model numbers is designated as the prioritycontroller. In one example, the generator controllers exchange capacityratings of output (e.g., 10 KW, 20 kW) or fuel (e.g., 5 gallon, 10gallon) and the highest (or lowest) capacity is designated as thepriority controller. In one example, the generator controllers exchangecurrent output levels and the highest (or lowest) capacity is designatedas the priority controller. In one example, the generator controllersexchange operation history (e.g., total operation hours, installationdates, time since last start, or another description of the lifetime ofthe generators) and the newest (or oldest) lifetime is designated as thepriority controller. In another example, the priority negotiationalgorithm may randomly select a controller as the priority controller.

In systems with more than two generators, the priority negotiationalgorithm may assign several levels of priority using any of theseexamples. The priority list of several generators may be stored inmemory by the generator controllers.

In another example, logic at the circuit breaker (e.g., a utilitycontroller or switch controller 103) may execute the prioritynegotiation algorithm using any of these examples. Alternatively, thelogic at the circuit breaker may designate priority using a first toarrive rule. The generator controller associated with the firstgenerator to close to the generator bus 11 and be visible to the logicat the circuit breaker is designated as the priority controller. Inanother example, the logic at the circuit breaker may designate theclosest (relative spatial position) generator controller as the prioritycontroller. Relative spatial position may be determined using a globalpositioning system (GPS) or through a response time for a ping sent tothe generator controllers.

In another example, the generator controllers may send a permissionmessage before sending a command to the circuit breaker 12. Thepermission message may be sent between generators or to the utilitycontroller. The permission message asks whether the other controllersare already designated as priority. If so, the sending controllerdesignated itself as a secondary controller. If not, the sendingcontroller designates itself as primary controller.

The priority may be set by relay logic (e.g., throwover relay) externalto the generator controllers and utility controllers. In this example,two or more generator controllers may attempt to control the utilitybreaker 12. The relay logic determines priority by selecting a controlsignal from one of the generator controllers. The selection may be basedon heartbeat signals (e.g., periodically changing digital signal) fromthe generator controllers.

FIG. 2 also illustrates an example system including redundantcommunication paths. Any of the devices in the system may communicatewith any other device in the system through two or more communicationpaths. For example, generator controller 100 a may communicate withgenerator controller 100 b through communication path 21 b. However, aredundant communication path 21 a could also be used to reach generatorcontroller 100 b through switch controller 103. Thus, if communicationpath 21 a fails, the generator controllers are still operable tocommunicate. The redundant communication path 21 a may be longer thancommunication path 21 b. Other arrangement other redundant communicationpaths may be used.

In addition or in the alternative to redundant generator controllers andredundant communication paths, other levels of redundancy may be used inthe generator system. For example, redundant circuit breakers mayprovide backup switches to open or close an electrical path. Theredundant circuit breakers may be in parallel or in series. Seriescircuit breakers may be used to open an electrical path. If one circuitbreaker fails and is stuck closed, the other circuit breaker may beswitched to open the path. Parallel circuit breakers may be used toclose an electrical path. If one circuit breaker fails and is stuckopen, the other circuit breaker may be switched to close the path. Inanother example, the generators or circuit breakers may have redundantsets of contacts.

FIG. 3 illustrates an example system including redundant generatorcontrollers. In addition to the generator controllers 100 a-b, thegenerators 101 a-b include alternators 15 a-b, and engines 19 a-b. Thealternators 15 a and 15 b may be electromechanical devices. Thealternators 15 a and 15 b may include a rotating magnetic field and astationary armature, a rotating armature with a stationary magneticfield, or a linear alternator. The engines 19 a and 19 b may be poweredby gasoline, diesel fuel, or gaseous fuel. The gaseous fuel may beliquefied petroleum gas (LPG), hydrogen gas, natural gas, biogas, oranother gas. The LPG may be or include primarily butane, primarilypropane, or a mixture of hydrocarbon gases. The hydrogen gas may includehydrogen mixed with air or oxygen. The hydrogen gas may be mixed withanother fuel when delivered to the engine. Natural gas (e.g., compressednatural gas (CNG)) may be a hydrocarbon gas mixture. Biogas may be a gasproduced by the breakdown of organic material. Other variations arepossible.

Each of the generator controllers 100 a-b may be connected to thecomponents of both (or more) generators. For example, generatorcontroller 100 a is connected to engine 19 a and alternator 15 a. Thegenerator controller 100 a may control the ignition, speed and otheroperation of the engine 19 a, and the field winding current and otherparameters of the alternator 15 a. However, the generator controller 100a may also control the operation of engine 19 a and parameters ofalternator 15 a.

The two controllers may also be directly connected to one another. Thecontrollers may exchange status signals every predetermined time period(e.g., 100 ms, 1 second, 10 seconds, or another value). When the statussignals indicate a failure, or either controller stops receiving statussignals from the other controller, that controller is operable toseamlessly take over for the failed controller, for example, by sendingcommands to the failed generators engine and alternator.

The status signals may include different types of information and bereceived from a variety of devices. Status signals may include discoverydata, operating parameters, measured data, or other information, and thestatus signals may be received from another generator, a centralcontroller, a utility, or another device. The discovery data may beavailability signals, connection information, or both.

An availability signal for a utility may include data indicative ofwhether or not the utility is available to supply power to the bus 11.Likewise, an availability signal for a generator may include dataindicative of whether the generator is available to supply power to thebus 11. The status signal received from the bus 11 may include multipleavailability signals from multiple devices.

The connection information may include a connection status for variousdevices. The connection status may include data indicative of whetherthe device is connected to the bus 11. The connection information mayinclude a switch setting for a breaker such as breakers 13 a and 13 b.The switch stetting may indicate an ON status, an OFF status, an openstatus, or a closed status. The connection status may be received fromcontrollers 100 a and 100 b or directly from the circuit breakers.

FIG. 4 illustrates an example generator controller 100 of the system forredundant control. The controller 100 may correspond to one or more ofgenerator controller 100 a, generator controller 100 b, switchcontroller 103, or another device. The controller 10 may include aprocessor 300, a memory 302, and a communication interface 303. Thegenerator controller 10 may be connected to a workstation 309 or anotherexternal device (e.g., control panel) and/or a database 307. Optionally,the generator controller 10 may include an input device 305 and/or asensing circuit 311. The sensing circuit 311 receives sensormeasurements for the operation of the generator or connected generators.Additional, different, or fewer components may be included.

The memory 302 may store data received through the communicationinterface 303 from the other generator controllers or directly fromsensors or other components of the other generators. The processor 300may extract an identifier, operating parameters, or peer commands fromanother generator from the received data. The processor 300 maydetermine that the other generator has experienced a failure from thereceived data. Based on the failure the processor 300 may generate andtransmit commands for the other generator.

The processor 300 may determine the status of circuit breakers based ondata monitored from the other generator controllers. The processor 300may determine when the circuit breaker is not receiving commands fromthe other generator controllers. This may be based on an absence ofcommunication from other generator controllers or based on an error codereceived from one or more other generator controllers.

The memory 302 may store operating parameters of the generators,identifiers for the generators, or a peer generator command from anothergenerator. The memory 302 may log received operating states for theparallel generators. A portion of the memory 302 may be assigned to eachgenerator in a set of parallel generators. Possible operating states mayinclude disconnected, connected, running, disabled, an error identifier,over speed, a speed value, an output value, or a phase angle.

FIG. 5 illustrates example flowchart for operation of the redundantcontroller of FIG. 4. The methods in FIG. 7 may, in some instances, beimplemented as logic or software executable by a controller, such ascontroller 10. Additional, different, or fewer acts may be provided. Theacts may be performed in the order shown or other orders. The acts mayalso be repeated.

At act 5101, a generator controller detects a breaker status for abreaker connecting a distribution bus to an external source. Theexternal source may be another generator, a utility, or another localsource such as wind power or solar power. The distribution bus may be agenerator bus as shown in FIGS. 1-3 or a connection between thegenerator and the load. The breaker status may identify whether thebreaker is open or closed. Alternatively, the breaker status mayidentify whether the breaker is tripped, charged, in manual mode, oranother mode.

At act 5103, the generator controller receives data from the othergenerator controller related to operation of the second generator. Thedata may be communications between the other generator controller andthe generator breaker. The data may be operating parameters of the othergenerator controller. The generator controller may analyze the data todetermine that the other generator controller has failed or that theexternal breaker is no longer receiving communication from the othergenerator controller.

At act 5105, the generator controller generates a command forcontrolling the breaker for the external source in response to thebreaker status or the data related to operation of the second generator.In addition or alternatively, the generator controller may generate acommand for shedding a portion of a load. Because one of the generatorshas failed, a capacity of the generator system has reduced.

The processor 300 may include a general processor, digital signalprocessor, an application specific integrated circuit (ASIC), fieldprogrammable gate array (FPGA), analog circuit, digital circuit,combinations thereof, or other now known or later developed processor.The processor 300 may be a single device or combinations of devices,such as associated with a network, distributed processing, or cloudcomputing.

The memory 302 may be a volatile memory or a non-volatile memory. Thememory 302 may include one or more of a read only memory (ROM), randomaccess memory (RAM), a flash memory, an electronic erasable program readonly memory (EEPROM), or other type of memory. The memory 302 may beremovable from the network device, such as a secure digital (SD) memorycard.

In addition to ingress ports and egress ports, the communicationinterface 303 may include any operable connection. An operableconnection may be one in which signals, physical communications, and/orlogical communications may be sent and/or received. An operableconnection may include a physical interface, an electrical interface,and/or a data interface.

The communication interface 303 may be connected to a network. Thenetwork may include wired networks (e.g., Ethernet), wireless networks,or combinations thereof. The wireless network may be a cellulartelephone network, an 802.11, 802.16, 802.20, or WiMax network. Further,the network may be a public network, such as the Internet, a privatenetwork, such as an intranet, or combinations thereof, and may utilize avariety of networking protocols now available or later developedincluding, but not limited to TCP/IP based networking protocols.

While the computer-readable medium (e.g., memory 302 or database 307) isshown to be a single medium, the term “computer-readable medium”includes a single medium or multiple media, such as a centralized ordistributed database, and/or associated caches and servers that storeone or more sets of instructions. The term “computer-readable medium”shall also include any medium that is capable of storing, encoding orcarrying a set of instructions for execution by a processor or thatcause a computer system to perform any one or more of the methods oroperations disclosed herein.

In a particular non-limiting, exemplary embodiment, thecomputer-readable medium can include a solid-state memory such as amemory card or other package that houses one or more non-volatileread-only memories. Further, the computer-readable medium can be arandom access memory or other volatile re-writable memory. Additionally,the computer-readable medium can include a magneto-optical or opticalmedium, such as a disk or tapes or other storage device to capturecarrier wave signals such as a signal communicated over a transmissionmedium. A digital file attachment to an e-mail or other self-containedinformation archive or set of archives may be considered a distributionmedium that is a tangible storage medium. Accordingly, the disclosure isconsidered to include any one or more of a computer-readable medium or adistribution medium and other equivalents and successor media, in whichdata or instructions may be stored. The computer-readable medium may benon-transitory, which includes all tangible computer-readable media.

In an alternative embodiment, dedicated hardware implementations, suchas application specific integrated circuits, programmable logic arraysand other hardware devices, can be constructed to implement one or moreof the methods described herein. Applications that may include theapparatus and systems of various embodiments can broadly include avariety of electronic and computer systems. One or more embodimentsdescribed herein may implement functions using two or more specificinterconnected hardware modules or devices with related control and datasignals that can be communicated between and through the modules, or asportions of an application-specific integrated circuit. Accordingly, thepresent system encompasses software, firmware, and hardwareimplementations.

In accordance with various embodiments of the present disclosure, themethods described herein may be implemented by software programsexecutable by a computer system. Further, in an exemplary, non-limitedembodiment, implementations can include distributed processing,component/object distributed processing, and parallel processing.Alternatively, virtual computer system processing can be constructed toimplement one or more of the methods or functionality as describedherein.

As used in this application, the term ‘circuitry’ or ‘circuit’ refers toall of the following: (a) hardware-only circuit implementations (such asimplementations in only analog and/or digital circuitry) and (b) tocombinations of circuits and software (and/or firmware), such as (asapplicable): (i) to a combination of processor(s) or (ii) to portions ofprocessor(s)/software (including digital signal processor(s)), software,and memory(ies) that work together to cause an apparatus, such as amobile phone or server, to perform various functions) and (c) tocircuits, such as a microprocessor(s) or a portion of amicroprocessor(s), that require software or firmware for operation, evenif the software or firmware is not physically present.

This definition of ‘circuitry’ applies to all uses of this term in thisapplication, including in any claims. As a further example, as used inthis application, the term “circuitry” would also cover animplementation of merely a processor (or multiple processors) or portionof a processor and its (or their) accompanying software and/or firmware.The term “circuitry” would also cover, for example and if applicable tothe particular claim element, a baseband integrated circuit orapplications processor integrated circuit for a mobile phone or asimilar integrated circuit in server, a cellular network device, orother network device.

Processors suitable for the execution of a computer program include, byway of example, both general and special purpose microprocessors, andanyone or more processors of any kind of digital computer. Generally, aprocessor may receive instructions and data from a read only memory or arandom access memory or both. The essential elements of a computer are aprocessor for performing instructions and one or more memory devices forstoring instructions and data. Generally, a computer may also include,or be operatively coupled to receive data from or transfer data to, orboth, one or more mass storage devices for storing data, e.g., magnetic,magneto optical disks, or optical disks. Computer readable mediasuitable for storing computer program instructions and data include allforms of non-volatile memory, media and memory devices, including by wayof example semiconductor memory devices, e.g., EPROM, EEPROM, and flashmemory devices; magnetic disks, e.g., internal hard disks or removabledisks; magneto optical disks; and CD ROM and DVD-ROM disks. Theprocessor and the memory can be supplemented by, or incorporated in,special purpose logic circuitry.

The illustrations of the embodiments described herein are intended toprovide a general understanding of the structure of the variousembodiments. The illustrations are not intended to serve as a completedescription of all of the elements and features of apparatus and systemsthat utilize the structures or methods described herein. Many otherembodiments may be apparent to those of skill in the art upon reviewingthe disclosure. Other embodiments may be utilized and derived from thedisclosure, such that structural and logical substitutions and changesmay be made without departing from the scope of the disclosure.Additionally, the illustrations are merely representational and may notbe drawn to scale. Certain proportions within the illustrations may beexaggerated, while other proportions may be minimized. Accordingly, thedisclosure and the figures are to be regarded as illustrative ratherthan restrictive.

While this specification contains many specifics, these should not beconstrued as limitations on the scope of the invention or of what may beclaimed, but rather as descriptions of features specific to particularembodiments of the invention. Certain features that are described inthis specification in the context of separate embodiments can also beimplemented in combination in a single embodiment. Conversely, variousfeatures that are described in the context of a single embodiment canalso be implemented in multiple embodiments separately or in anysuitable sub-combination. Moreover, although features may be describedabove as acting in certain combinations and even initially claimed assuch, one or more features from a claimed combination can in some casesbe excised from the combination, and the claimed combination may bedirected to a sub-combination or variation of a sub-combination.

One or more embodiments of the disclosure may be referred to herein,individually and/or collectively, by the term “invention” merely forconvenience and without intending to voluntarily limit the scope of thisapplication to any particular invention or inventive concept. Moreover,although specific embodiments have been illustrated and describedherein, it should be appreciated that any subsequent arrangementdesigned to achieve the same or similar purpose may be substituted forthe specific embodiments shown. This disclosure is intended to cover anyand all subsequent adaptations or variations of various embodiments.Combinations of the above embodiments, and other embodiments notspecifically described herein, will be apparent to those of skill in theart upon reviewing the description.

It is intended that the foregoing detailed description be regarded asillustrative rather than limiting and that it is understood that thefollowing claims including all equivalents are intended to define thescope of the invention. The claims should not be read as limited to thedescribed order or elements unless stated to that effect. Therefore, allembodiments that come within the scope and spirit of the followingclaims and equivalents thereto are claimed as the invention.

I claim:
 1. An apparatus comprising: a circuit to provide a conductivepath to a bus connected to a first generator and a second generator; anda first generator controller configured to control the first generatorand to monitor communication from a second generator controller for thesecond generator, the first generator controller configured to identifya failure in the second generator based on the monitored communication.2. The apparatus of claim 1, wherein the first generator controller isconfigured to issue a command for the second generator based on thefailure.
 3. The apparatus of claim 1, wherein the bus is configured toprovide a communication path for the communication from the secondgenerator controller.
 4. The apparatus of claim 1, wherein the secondgenerator controller is configured to control the second generator andto monitor communication from the first generator controller for thefirst generator.
 5. The apparatus of claim 1, wherein the failureindicates that the second generator is not sending one or more circuitbreaker commands.
 6. The apparatus of claim 1, wherein the communicationfrom the second generator controller include one or more operatingparameters for the second generator.
 7. The apparatus of claim 6,wherein the one or more operating parameters includes a speed, an outputvoltage, an output phase angle, a breaker status of the sendinggenerator or measured data collected from a voltage sensor, a currentsensor, a tachometer, a torque sensor, a deflection sensor, adynamometer, a positional sensor, or a revolution sensor.
 8. Theapparatus of claim 1, wherein the communication from the secondgenerator controller include one or more load shedding commands or oneor more error codes.
 9. The apparatus of claim 1, wherein thecommunication from the second generator controller include messages thatoccur every predetermined period and the failure in the second generatoris based on a lack of messages for at least the predetermined period.10. The apparatus of claim 1, wherein the first generator controller isconfigured to generate a start command for the second generator based onthe failure.
 11. A method comprising: controlling, using a firstgenerator controller, a first generator; monitoring, using the firstgenerator controller, communications from a second generator controllerfor a second generator; and identifying, using the first generatorcontroller, a failure in the second generator based on the monitoredcommunications.
 12. The method of claim 11, further comprising:providing a conductive path to a bus connected to the first generatorand the second generator.
 13. The method of claim 12, wherein theconductive path is a communication path for the communications from thesecond generator controller.
 14. The method of claim 11, furthercomprising: generating a command for the second generator based on thefailure.
 15. The method of claim 11, wherein the failure indicates thatthe second generator is not sending one or more circuit breakercommands.
 16. The method of claim 11, wherein the communications fromthe second generator controller include one or more load sheddingcommands or one or more error codes.
 17. The method of claim 11, whereinidentifying, using the first generator controller, the failure in thesecond generator based on the monitored communications comprises:determining whether the communications from the second generatorcontroller occur every predetermined time period, the failure in thesecond generator being based on a lack of communication for at least thepredetermined time period.
 18. The method of claim 11, furthercomprising: generating a start command for the second generator based onthe failure.
 19. A system comprising: a bus connected to a firstgenerator and a second generator; and a first generator controllerconfigured to control the first generator and to monitor communicationsfrom the second generator, the first generator controller configured toidentify a failure in the second generator based on the monitoredcommunications.
 20. The system of claim 19, further comprising: a secondgenerator controller configured to control the second generator and tomonitor communications from the first generator, the second generatorcontroller configured to identify a failure in the first generator.